Shears



J. EWART Aug. 1, 1950 SHEARS Filed Aug. 2, 1945 a w 1v Patented Aug. 1, 1950 .SHEARS .John Ewart, Johannesburg, Transvaal, Union of South Africa, assignor to .Harold McCartney Lawrence, Johannesburg, Transvaal, Union .of

South Africa ApplicationAugust 2, 1945, Serial No. 608,468 In'the Union of SouthAfrica September 27, 1944 This invention relates to shears ifor cutting sheet material; of thekind comprising pivoted blades, and including hand shears. The utility of the invention is developed best in the cutting of sheetmetal, and correspondingly in the .case of other sheet material to the extent that the latter resembles sheet metal in being highly resistive to deformation within its own plane and offering substantial resistance to being bent out of its plane.

The object of the invention is to facilitate the movement of the out edges of the material, or one of such edges, away from the blades; and .to enable bending of one :of the severed portions of the sheet to be avoided.

According to the invention, in .each member of the shears, the thickness of the blade .is on one side of the shearing plane perpendicular to the pivot axis and the thickness of the hub is on the other side of said plane. The hub bearing surface and the blade shearingsurface maybe substantially in the same plane but .faced. oppositely toone another.

The transportation of the thickness of each member from one side of the shearing plane to the other causes the formation of a blade shoulder and in accordance with a feature of the invention, said shoulder of one, at least, of the memhers is limited as regards its position in the .direction from the back edge of the cutting .blade towards the cutting edge thereof, so that it does not extend over the line of the cutting edge of. the blade.

The fact of the blade thickness and the .hub thickness being on the opposite sides of the shearing plane eliminates said hub .as a ,possible obstacle to the travel of, the cut edge of a .work

sheet, away from the related blade cutting edge; whilst the limitation specified in the lastpreceding paragraph prevents the blade shoulder from being an obstacle.

In order to prevent obstruction by the pivot pin and the hub of the second shears member, one of the members is selected as the one from which the cut edges of the work formed byit shall be free to pass away without necessary deviation from a work plane parallel to the pivot axis and including the cutting edge of said selected member; and the pivot axis ispositioned to be distant from said work plane or from the line -.of the selected cutting edge in the :direction .from the back of the selected blade towards the cutting edge thereof. Also the .hub .of the non-selected element is so limited in .itsradial distance from the pivot axis as to .stand clear of such work 2 Claims. (Cl.30-257) 2 plane or cutting edgeline and thereby leave between itself and the blade shoulder of the selected blade, a gap for the selected cut edge to pass through.

Thehub shoulder of the selected blade may be arranged to be tangential to the cutting edge of, the non-selected blade so as to minimize bending of the non-selected-cut edge of the work sheet. On theother hand such shoulder may be considerablyextended beyond the tangential position in order to bend such non-selected out edge. I

With the object of holding the blade :edges in contact, adjustable spacing means may be provided betweenthe hub bearing surfaces; such as a washer which may be exchanged with another of difierent thickness to adjust the spacing.

.In the case of hand shears, both members in clude handles that are crossed at the pivot in the usual manner and may be arranged to be wholly or to a large extent on the same side of the work plane as the pivot. The portions of said handles distant from the pivot may be arranged to co-operate, also with the object of holdingthe blade edges in contact. For this purpose they may be :alined .and arranged to contact at their internal surfaces, said internal surfaces being sloped relatively to the direction of the approachof the terminal portions soas to spread the latter apart laterally.

There may be a spring between the handles, tending constantly to force the latter apart.

A pair of hand actuated metal cutting shears is shown in the accompanying drawing by way of an example.

,In the drawings- Figure I is a perspective view of the shears from one side I Figure .II is a similar view from the opposite side I ,Figure III is a cross section through III-III Figure I,

Figure IV is a cross section of the shears membertaken on.I"\ '--.I.V.of Figure I,

.Figure V is-an enlarged view oftthe end of the handles viewed from the section V-V Figure I.

Figure VI is a fragmentary perspective view similar to Figure IIshowinga modification of the invention. V I l The shears comprises the .two elements 2, 3. The member .2 comprises, as integral parts, the blade 4 with its shearing surface .5 terminating at the cutting edge 6; the hub portion! providing the plane hub bearing surface 8; and the handle 9extending backward from the, hub portion 1 with reference to the \blade 4 extending forwardly from said hub portion. The member 3 comprises the generally similar combination of the blade l 53 with its surface H and cutting edge E2; the hub portion l3 with its plane bearing surface I l; and

the handle 15.

The members 2, 3 are pivotally connected by the pivot bolt it passed through the hubs I, it; said bolt having the head i! at one end and the locking nuts l8 at the other end. The bolt axis is indicated by l9. Said hubs, head, and nuts, and to some extent the handles 9 and i5, occupy a substantial space that in ordinary shears causes them to stand in the way of one or both the cut edges of the work as said edges pass relatively backward from the point 2.3 at which the cutting edges 6, l2 meet at any moment.

The structure described defines the shearing of the member 2 is positioned on the opposite side of said shearing plane S-S from the blade d of that member. In other words (assuming the hub bearing faces 8, M to be plane, as they are in the example) while the blade face 5 and the hub bearing face 8 are both materially in said plane S-S, the thickness T of the blade and, the thickness t of the hub extend from said plane S-S in opposite directions as shown specially in Figure III. Similarly the hub portion is and the blade iii of the member 3 are respectively on opposite sides of the plane SS, and each faces oppositely to the corresponding parts of the member 2.

When sheet metal is cut at said cutting point 29, the cut edges Zi 29, separate from one another at said point in the direction perpendicular to the plane of the metal sheet 22, and said edges make an angle with one another corresponding to the angle which the blade edges'fi, i 2 make with one another at that moment.

It is convenient to arrange that such angle of separation is impressed substantially wholly on one of the out edges and that the other out edge be selected to continue without deviation from the general plane of the uncut portion of the sheet.

The pair of shears is shown in Figures I andII as being used by resting it on the table 23 and with the blade 4 standing vertically and square with the substantially horizontal sheet 22 of metal that is being out along a straight line '24. This attitude of the shears is used in the following specification as a standard for describing positions.

22 indicates the uncut portion of the metal sheet. 222:; indicates the more important severed portion of the metal sheet the cut edge 2Ia of which it is desired to keep free from being bent sharply enough or in a direction such as to impair the suitability of portion 22a for its intended purpose; the portion 221) being for instance waste or of minor importance. The cutting edge 6 of blade 4 is shown as being held horizontally with the sheet portion 22 resting on it. The plane parallel with the axis l9 and including said edge 6-is here referred to as the work plane; and is represented in the drawing by said portion 22.

In the example, the blade 4 of the member 2 is selected as the blade from which the cut edge 2 la of the Work can move away, substantially in line with the cutting edge 6 in plan, and without obstruction by the hub and associated structure. The displacement of the huh I of this element eliminates said hub I as a possible obstruction. Any suitable arrangement is made for displacing other possibly obstructive parts; and in the example shown this is provided for by the known expedient of displacing the pivot bolt 16, the hub it of member 3 and the handles 9 and 15 above the plane of the work plane.

With this object the hub portion 1 is cranked upward relatively to the cutting edge 6. The pivot bolt I6 is positioned well above the work plane, and the handle I 5 of member 3 is extended materially in line with the blade l0 so that when being reciprocated it does not come below the work plane to any. important extent, or if it does, it does so at a di'stan'ce from the blades 4 and I0 such that the sheet portion 22a can bend downwar'din a large radius that is not apt to form a:

permanent set. v

The handle 9 of the member 2 is cranked at both in elevation'to come reasonably parallel with the, handle [5; and also in plan to compensate for the offset of the hub l and thereby bring the handles 9' and I5 vertically above one another.

The ofisetting in each member, of the hub from the blade, causes each member 2 and 3 to include a portion 26 andEBa respectively of double thickness. In the member 2, the shoulders bounding said portion 26 are identified as the blade shoulder 2i and the'hub shoulder 28.

The blade shoulder 21 is arranged to be not above the Work plane; and it is convenient to arrange; it in line in elevation with the cutting edge 8, when it does not encroach on the metal 26. The hub l3 of the member 3 onthe other hand is arranged to be spaced above the work plane in all its positions of oscillation; and the significant portion 29 of its edge may be shaped as an arc centred at the axis I9, and of such limited radius as to leave, between it and the blade shoulder 21!, the gap 3i! through which the cut edge Zia passes without obstruction.

With regard to the hub shoulder 28, this may be an arc tangential (inside elevation) to the cutting edge l2 of the member 3, in which case it does not deviate the cut edge 2 lb further from the path of movement imparted to said edge 21b by said cutting edge i2. On the other hand, it is often desirable to give said out edge Zlb a further deviation which causes'the out strip 22b to curl up. Bush further deviation may beset up by widening said shoulder 28 radially from I!) beyond said tangential position as indicated at fisminFigure v1;

, 3| indicates athin washer whichimay be inserted between the hub bearing surfaces 8,14. Its thickness isso. adjusted as to hold said bearing surfaces apart to the extent necessary to en sure that the blade edges 6 and l2 see eye to eye. The adjustment is made by substituting a thicker washer, or inserting a shim; to take vup wean.

The terminal portions 32, 33 of the handles 9,

[5 are in the usual way bent around to come materially into vertical alinement'wi th one another, Their internal surfaces 34, 35 are sloped across their direction of approach; and it' is arranged that during the closing'oi the blades, said sloped surfaces 34, 35 contact with andprss onone a'nother. The resulting elastic spreading apart of the handles horizontally, assists in keeping the blades eye to eye.

The fact that the handles 9, 15 are above the work plane and are not in the way of the cut portions 22a, 22b enables the compression spring 36 to be inserted between them. Said spring 36 constantly urges the handles apart to open the blades and thus facilitates the operation of the shears by avoiding the necessity of manually pressing the handles apart after each cut. A stop 3'! limits the separation of the handles.

I claim:

1. Shears consisting of a pair of opposed shear members, each member comprising a blade and a hub integral with the blade, the members being pivotally connected to one another at an axis intersecting their hubs, the blade edges defining a shearing plane perpendicular to the pivot axis, each member having the thickness of its blade on one side of the said shearing plane and the thickness of its hub on the other side of said plane, handles extending from the hubs, the terminal portions of said handles being alined and arranged to contact at their internal surfaces, said internal surfaces being sloped relatively to the direction of the approach of the terminal portions so as to spread the latter apart laterally.

2. Shears consisting of a pair of opposed shear members, each member comprising a blade and a hub integral with the blade, the members being pivotally connected to one another at an axis intersecting their hubs, the blade edges defining a shearing plane perpendicular to the pivot axis,

each member having the thickness of its blade on one side of the said shearing plane and the thickness of its hub on the other side of said plane; said axis being positioned to be distant from the cutting edge of one blade in the direction from the back of said blade towards the cutting edge of said blade, handles extending from the crossed hubs, the terminal portions of said handles being alined and arranged to contact at their internal surfaces, said internal surfaces being sloped relatively to the direction of the approach of the terminal portions so as to spread the latter apart laterally.

JOHN EWART.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 25,508 Heinisch Sept. 20, 1859 513,542 Stockman Jan. 30, 1894 540,464 Stockman June 4, 1895 853,681 Cook et al May 14, 1907 1,955,134 Kowalski Apr. 17, 1934 2,387,053 Brown Oct. 16, 1945 FOREIGN PATENTS Number Country Date 639,533 France Mar. 110, 1928 

